The present invvention is directed to a method of making a reaction product containing phenol formaldehyde resole and its use in combination with a vinyl pyridine latex.sup. 2 for tire cord dips. The phenol formaldehyde resole.sup. 1 is made by a process without isolating any of the products. The reaction product is referred to herein as a phenol formaldehyde resin. A cord coated with the dip composition of the present invention is used to reinforce rubber products such as tires. FNT .sup.1 Resole is used in its generic sense to describe a family of species. FNT .sup.2 Latex is used in its generic sense to describe a family of species.
Cord dips based upon the use of a blend of resorcinol formaldehyde resole and a vinyl pyridine copolymer latex are very effective and are widely used.
Cord dips based upon trimethylol phenol are also known, see U.S. Pat. Nos. 3,888,805 and 3,930,095 of van Gils and Kalafus. Cord dips utilizing a mixture of phenol formaldehyde resin and resorcinol formaldehyde resin with an aldehyde latex are disclosed in U.S. Pat. No. 2,748,049 of Kalafus.
While the cord dips of the prior art are quite useful and provide good adhesion between cords and rubber, there are certain problems inherent in their use. Resorcinol, for example, is relatively expensive when compared with phenol. In addition there is only one commercial supplier of resorcinol in the U.S., if not the world. Supplies of resorcinol were recently, though not presently, limited. In addition resorcinol formaldehyde resoles are unstable and have a shelf life of only a few days even at low concentration. Vinyl pyridine is expensive. Trimethylol phenol can be obtained at again a relative high price if one can induce a supplier to manufacture the trimethylol phenol. Trimethylol phenol is not presently being manufactured, is unstable, condensing into a resin on room temperature storage and must be refrigerated if storage is contemplated.
In the manufacture of trimethylol phenol, an excess of formaldehyde is added in the first prior art step. The excess is then removed. The disposal of the removed formaldehyde results in a disposal or a water pollution problem. The removal of the formaldehyde also results in a time consuming and expensive process step. Catalyst removal steps of the prior art have involved ion exchange treatment. The same can be said of the salt forming and crystallization steps employed to isolate the trimethylol phenol salts. The purification process involved in isolating the trimethylol phenol generates even more waste product containing phenols and formaldehyde. Phenolic and formaldehyde pollutants are very difficult, if not impossible, to remove by sewage treatment and by the water treatment normally used for drinking water supplies. This often results in off-taste and odor in drinking water. The off-taste and odor is carried over even by distillation of the polluted drinking water supply.